In modern office designs it is desirable to have furniture, such as work surfaces, shelves, cabinets and the like, removably mounted to the interior walls of a building and/or the freestanding walls the so-called "open plan" office system. To this end, the furniture elements, or supporting brackets to which the same are attached, are provided, on the rear portions thereof, with hooks or tabs adapted to engage vertical slotted standards rigidly secured to the interior or freestanding walls. In order to circumvent damage to the furniture or injuries to workers which may result from inadvertent disengagement of the hooks or tabs from the vertical standards, it is desirable to provide a device capable of locking the hooks or tabs in engagement with the slots of the standard. Utilization of a device which requires, during assembly of the furniture to the vertical standard, a conscious manual step on the part of the individual conducting such installation may result in disengagement of the furniture and thus damage and injury in that such individual, due to temporary memory loss, may not dispose the device in locked condition. To eliminate the possibility of human error and insure that the locking device is always set in the locked condition when the furniture is mounted to the wall, it is desirable to employ a locking device which is automatically set in locked condition upon the installation of the furniture to the vertical slotted standard but yet which can be unlocked to remove the furniture piece from the standard.
Devices for securely locking furniture and other appurtenances to supporting structures are known. These devices, however, are not automatically disposed in locked condition when the furniture is mounted to the support structures. Rather, to set the devices in locked condition, the individual installing the furniture must, subsequent to mounting the furniture to the supporting structure, perform some manual operation.
For example, the U.S. Pat. No. 4,048,768 to Good, issued Sept. 20, 1977, discloses a device for locking the hooks of an appurtenance to the slots of a vertical standard. A bracket is rigidly attached to the appurtenance and has downwardly depending tabs for engaging the slots of the standard. The locking device comprises a hook pivotably attached to the bracket and adapted to be removably received within a slot of the vertical standard. The appurtenance is locked to the vertical standard by first inserting the tabs of the bracket into the slots of the standard and subsequently forcibly inserting the hook into an adjacent slot above the slot housing the uppermost tab of the bracket.
The Fenwick et al U.S. Pat. No. 3,601,432, issued Aug. 24, 1971, discloses a frame structure for a department store display fixture comprising vertical and horizontal members and a locking device for rigidly securing the vertical members to the horizontal members. The vertical members have a number of vertically disposed slots. Rigidly secured to opposite ends of each horizontal member is a brace from which protrude two hooks vertically spaced so as to be registrable with the slots in the vertical member. The locking device comprises a bar pivotably mounted to the brace and having a horizontal tab which rests directly above the lowermost hook of the brace and a flange to facilitate actuation of the bar. When the hooks are inserted into the slots of the vertical member, there remain spaces in the slots above the hooks, the bottom space to be filled with the horizontal tab of the locking device. The insertion of the tab is accomplished by subsequently applying force to the flange so as to cause pivoting of the bar to the locked position.
Finally, the patent to Stroh 3,730,108, issued May 1, 1973, discloses a shelf support structure including a vertical slotted standard, a wire shelf and a mechanism for locking the shelf to the standard. The mechanism comprises a bracket rigidly secured to the shelf and having a number of downwardly-depending hooks received within the slots of the standard and a device pivotably mounted to the bracket and adapted to engage an unoccupied slot of the standard to prevent upward vertical movement of the shelf and thus inadvertent dislodgement of the hooks from the standard. Like the locking devices in Good and Fenwick et al, the locking device in Stroh is manually set in the locked condition after the appurtenance is mounted to the slotted standard.